llvm/lib/Target/Mips/MipsPreLegalizerCombiner.cpp

   1 //=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.cpp --------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This pass does combining of machine instructions at the generic MI level,
  10 // before the legalizer.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "MipsTargetMachine.h"
  15 #include "llvm/CodeGen/GlobalISel/Combiner.h"
  16 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
  17 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
  18 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
  19 #include "llvm/CodeGen/TargetPassConfig.h"
  20 #include "llvm/InitializePasses.h"
  21
  22 #define DEBUG_TYPE "mips-prelegalizer-combiner"
  23
  24 using namespace llvm;
  25
  26 namespace {
  27 class MipsPreLegalizerCombinerInfo : public CombinerInfo {
  28 public:
  29   MipsPreLegalizerCombinerInfo()
  30       : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
  31                      /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
  32                      /*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
  33   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
  34                        MachineIRBuilder &B) const override;
  35 };
  36
  37 bool MipsPreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
  38                                            MachineInstr &MI,
  39                                            MachineIRBuilder &B) const {
  40   CombinerHelper Helper(Observer, B);
  41
  42   switch (MI.getOpcode()) {
  43   default:
  44     return false;
  45   case TargetOpcode::G_MEMCPY_INLINE:
  46     return Helper.tryEmitMemcpyInline(MI);
  47   case TargetOpcode::G_LOAD:
  48   case TargetOpcode::G_SEXTLOAD:
  49   case TargetOpcode::G_ZEXTLOAD: {
  50     // Don't attempt to combine non power of 2 loads or unaligned loads when
  51     // subtarget doesn't support them.
  52     auto MMO = *MI.memoperands_begin();
  53     const MipsSubtarget &STI =
  54         static_cast<const MipsSubtarget &>(MI.getMF()->getSubtarget());
  55     if (!isPowerOf2_64(MMO->getSize()))
  56       return false;
  57     bool isUnaligned = MMO->getAlign() < MMO->getSize();
  58     if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
  59       return false;
  60
  61     return Helper.tryCombineExtendingLoads(MI);
  62   }
  63   }
  64
  65   return false;
  66 }
  67
  68 // Pass boilerplate
  69 // ================
  70
  71 class MipsPreLegalizerCombiner : public MachineFunctionPass {
  72 public:
  73   static char ID;
  74
  75   MipsPreLegalizerCombiner();
  76
  77   StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
  78
  79   bool runOnMachineFunction(MachineFunction &MF) override;
  80
  81   void getAnalysisUsage(AnalysisUsage &AU) const override;
  82 };
  83 } // end anonymous namespace
  84
  85 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
  86   AU.addRequired<TargetPassConfig>();
  87   AU.setPreservesCFG();
  88   getSelectionDAGFallbackAnalysisUsage(AU);
  89   MachineFunctionPass::getAnalysisUsage(AU);
  90 }
  91
  92 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
  93   initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
  94 }
  95
  96 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
  97   if (MF.getProperties().hasProperty(
  98           MachineFunctionProperties::Property::FailedISel))
  99     return false;
 100   auto *TPC = &getAnalysis<TargetPassConfig>();
 101   MipsPreLegalizerCombinerInfo PCInfo;
 102   Combiner C(PCInfo, TPC);
 103   return C.combineMachineInstrs(MF, nullptr);
 104 }
 105
 106 char MipsPreLegalizerCombiner::ID = 0;
 107 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
 108                       "Combine Mips machine instrs before legalization", false,
 109                       false)
 110 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
 111 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
 112                     "Combine Mips machine instrs before legalization", false,
 113                     false)
 114
 115 namespace llvm {
 116 FunctionPass *createMipsPreLegalizeCombiner() {
 117   return new MipsPreLegalizerCombiner();
 118 }
 119 } // end namespace llvm